Ladle lining

ABSTRACT

A ladle having a curved conical sidewall provided with a lining comprising stacked courses of refractory blocks disposed with horizontal top and bottom faces and provided with parallel front and back faces inclined at substantially the same angle as the ladle sidewall to provide a lining face which is smooth and continuous.

United States Patent 2,305,112 12/1942 Scott 52/245 3,421,749 1/1969Garber 266/43 X 3,429,487 2/1969 Tredenwick.... 266/43 X 3,294,38612/1966 Willenbrock 52/612 FOREIGN PATENTS 460,286 1926 Germany 1 10/] APrimary Examiner-John E. Murtagh Attorneys-Emory L. Groff and Emory L.Groff, Jr.

ABSTRACT: A ladle having a curved conical sidewall provided with alining comprising stacked courses of refractory blocks disposed withhorizontal top and bottom faces and provided with parallel front andback faces inclined at substantially the same angle as the ladlesidewall to provide a lining face which is smooth and continuous.

PATENTEDSEP m: 3,603; 050

(PRIOR ART) MYRON COLEMAN INVENTOR I BY ATTORNEY LADLE LINING Thisinvention relates generally to refractory blocks and more particularlyto an improved construction and method of arranging such blocks toprovide linings in ladles as used for molten steels and other materials.

The ladle of the present invention will be understood to be especiallyadapted for use in metallurgical processes involving the production ofsteels or alloys, such as by electric furnaces, and includes a workinglining comprising a plurality of specifically constructed refractoryblocks arranged in a manner to provide a ladle lining of vastly improvedstability and increased useful working life. The concept of thisinvention will be particularly appreciated when applied to those ladleshaving a diameter less than approximately 90 inches wherein asignificant shortcoming is presently evident.

Ladles for containing molten steel or alloys are provided with arefractory lining which must necessarily be arranged within the confinesof the circular or curved sidewall of the ladle in a manner most likelyto prevent the molten metal from penetrating to the outer metal shell ofthe ladle. The lining must perform this mission while being subjected toextreme fluctuating temperatures and the erosive action of the moltenmetal being poured into and out of the ladle and must withstand thisaction for as many successive heats as possible in order to reduce thefrequency of downtime required for repair or replacement of the lining.

Alternate methods of lining ladles with refractory block include usingeither soldier courses or a circular arrangement and several shapes ofrefractory block have been utilized in prior linings in efforts toachieve a more efficient installation, including straight, circle,universal and chord circle blocks. More recently, an improvedinterlocking block has been found to produce an advantageous ladlelining and forms the subject matter of my earlier patent (US. Pat. No.3,394,521, issued July 30, 1968). It has been acknowledged by thoseskilled in the art that this latter block structure yields a liningsuperior to those utilized heretofor which may be attributed to theeffective blockage against outward flow of molten metal offered by thenovel interlocked structure. However, a shortcoming has been observed,which also is apparent when using other prior art blocks in lining theconically curved sidewalls of ladles. The referenced problem isattributed to the inclination of the curved ladle sidewall or shellagainst which the refractory blocks are positioned. This inclinationexists within the range of 4l0 from the vertical and will be understoodto significantly affect the installation of the lining refractoryblocks, which have previously comprised vertical front and rear facesand horizontal top and bottom walls, whether these surfaces have beencurved or straight. With such an arrangement, it will follow that if theblocks are laid flat, that is with the top and bottom walls horizontal,then each succeeding course will be set back a significant distance withrespect to the next lowest course such that a ledge will extendoutwardly into the ladle between each pair of courses therebysignificantly reducing the effective thickness of the lining. The effectof this ledge will additionally be a consideration in view of theresidue removal operation to which the ladle will be subjected in thecase of an alloy plant. This periodic operation involves the mechanicalremoval of solidified alloy and slag from the interface of the liningand is usually accomplished with a power chisel tool, such as a jackhammer and it will be appreciated that in the case of theabove-described lining that the plurality of ledges projecting into theladle center will be struck by such a tool and removed along with thealloy and slag, thus reducing even more the effective amount ofrefractory lining present.

In order to correct the above arrangement leading to a reduction ineffective thickness, many linings have been constructed to reducecorbelling of the refractory blocks such that the front and back facesof all the blocks are disposed in two common planes, each parallel tothe inclined sidewall of the ladle shell. In this manner it will beunderstood that the top and bottom planar walls of each block, which areperpendicular to the front and back faces, will be disposed in planesinclined with respect to the horizontal or sloping downwardly from thefront face to the shell wall. The corbel effect is thus reduced in viewof the placement of a plurality of planar surfaces in a circular mannerand in a sloping plane. This prior art installation results in a liningwhich normally is most unstable and yields a triangular-shaped openingbetween the ends of each pair of adjacent blocks and which obviouslyleads to defeat of the very purpose of a ladle lining namely, theprevention of passage of the molten metal to the back face of the liningand the adjacent ladle shell. This relationship is due to the ladlesidewall inclination and the fact that each succeeding course of blocksis positioned to place its outer vertical face within a circle having aradius larger than that of the circle within which the preceding courseof blocks is positioned. Stated alternatively, the corbel effect isreduced due to the circular placement of the outer edge of each blocktop and bottom wall in a plane which is lower than the plane of theinner edge of these walls.

The construction of the present lining is further enchanced by the useof a bloating type of block. The bloating type may be classified as alow duty fireclay brick having high bulk density and low apparentporosity. While brick of higher refractoriness and lower reheatexpansion characteristics are sometimes used for lining ladles, they aresubject to possible joint penetration and hence may lead to difficultyin skull removal. This condition is lessened when bloating-type brick isused because of its inherent ability to expand at the surface atsteelmaking temperatures thus sealing the joints against metal and slagpenetration and forming virtually a monolithic lining. Life of the ladlelinings is, therefore, more consistent when bloating brick are used andless time is generally required for lining repairs or patching. Also,operation with fewer ladles may be possible without delay in tappingheats with the consistently high ladle life normally obtained frombloating-type brick.

Accordingly, one of the primary objects of the present invention is toprovide an improved ladle lining wherein the ladle includes a curvedconical sidewall or shell and the lining comprises a plurality ofrefractory blocks disposed in a plurality of stacked courses, each blockconstructed to provide a substantially continuous contact betweenjuxtaposed top and bottom walls thereof, as well as a single continuoussurface on both the front and back faces of the lining.

Another object of the present invention is to provide an improved ladlelining including a plurality of refractory blocks each of which isprovided with planar and parallel top and bottom walls, and front andrear faces which are parallel and inclined substantially in the samedegree as the inclination of the ladle sidewall.

Another object of the present invention is to provide an improved methodof lining ladles having a conically curved sidewall including the stepsof stacking a plurality of refractory blocks thereagainst and whereineach block is constructed to permit placing the blocks in a horizontalplane yet providing an inclined but smooth or planar front and back faceto the completed lining.

With the above and other objects in view which will more readily appearas the nature of the invention is better understood, the inventionconsists in the novel construction, combination and arrangement of partshereinafter more fully described, illustrated and claimed. i

A preferred and practical embodiment of the invention is shown in theaccompany drawing, in which:

FIG. 1 is a vertical section, partly broken away, and illustrates atypical ladle according to the prior art.

FIG. 2 is an enlarged view similar to FIG. 1 and discloses the ladlelining of the present invention.

FIG. 3 is a top perspective view of one form of refractory blockaccording to the present invention.

FIG. 4 is a top perspective view of another embodiment of the presentinvention.

FIG. 5 is a top perspective view of a further embodiment of the presentinvention.

Similar reference characters designate corresponding parts throughoutthe several figures of the drawing.

Referring now to the drawing, particularly FIG. 2, the present inventionwill be seen to comprise a ladle, generally designated A, which includesan outer metal shell 1 constructed with a conically curved configurationas is well known in the art. The instant arrangement will beparticularly appreciated when applied to the metallurgical environmentinvolving ladles having a diameter approximately between 57 and 90inches. This relatively small diameter results in a ladle wall of smallradius and thus a substantially sharp curvature and an emphasis of thecorbel effect. Combined with this curvature is a ladle wall inclinationof between 410.

Provided adjacent the inner surface of the metal shell I is the usualrefractory safety lining 2 which also extends across the bottom of theladle. A working floor lining 3 is provided across the bottom of theladle and forms the horizontal base upon which the working side lining,generally designated 4, is installed. The result of the referencedcorbel efiect is illustrated in the prior art arrangement shown in FIG.1 which in dicates in an exaggerated manner the unstable or irregularplacement of stacked courses of conventional refractory blocks in aladle having a conically curved sidewall and clearly illustrates theirregular spaces thus formed between the stacked blocks and which leadsto a relatively short life for the lining in view of the allowablepenetration of molten metal and slag therebetween.

The ladle lining as disclosed in FIG. 2, according to the presentinvention, will be seen to provide a lining face, generally designated5, comprising a smooth continuous curved and inclined surface extendingfrom the working floor lining 3 to a point adjacent the top of the ladleand likewise provides a similarly disposed lining back, generallydesignated 6, which will be seen to be parallel to the lining face 5 andforms a continuous curved and inclined surface in full contact with thejuxtaposed surface of the refractory safety lining 2.

It will be understood that the lining 4 as shown in FIG. 2 illustratesthe basic concept of the present invention and the arrangement showntherein would generally apply even though utilized in combination withrefractory blocks having various configurations when viewed in top plan.In this figure, a modified circle block is shown installed in the ladleA which block is illustrated on an enlarged scale in FIG. 4. The circleblock, generally designed 7, will be seen to include a top wall 8 andbottom wall 9 comprising congruent planar surfaces disposed parallel toone another and having arcuate inner and outer edges. The front face 10and back face 11, on the other hand, comprise curved surfaces, thelatter of which substantially corresponds to the approximate curvatureof the ladle shell 1. The important feature of the present inventionresides in the angular disposition of the front face 10 and back face 1l with respect to the top and bottom walls of the block as will be seenmost clearly in FIG. 2, wherein it is quite evident that the front andback faces, although parallel to one another, are inclined outwardly anamount approximately equal to the inclination of the ladle shell 1 withrespect to the horizontal. From the foregoing, it will be understoodthat the refractory block used in the subject lining comprises atransverse cross section having a configuration describing aparallelogram such that when each course of these blocks is installedwith a top and bottom wall in a horizontal plane, the front and backfaces thereof will be disposed parallel to the shell 1. Theabovedescribed structure insures that the outside and inside edges ofboth the top and bottom walls of the block are disposed in a commonhorizontal plane and thereby precludes the irregular or unstabledisposition of the assembled plurality of courses of blocks heretoforedescribed as producing the corbelling effeet.

In the prior art installation of FIG. I, the conventional rectangularcross section configuration of the refractory blocks clearly points outthe resultant assembly wherein the top and bottom walls of all theblocks are disposed normal to the ladle shell and thus in a plane whichis not parallel to the horizontal such that the inside and outside edgesof each refractory block are disposed in two different horizontal planesthereby producing a corbelling effect and the attendant unstable orirregular spacing between the plurality of blocks.

Although the modified circle block 7 of FIG. 4 would provide the mostintimate contact between the back face 11 thereof and the adjacent ladleshell 1, it will be understood that any of the other well-known types ofblocks may be constructed according to the present invention. This willinclude universal, straight, chord circle and tongue and groove orinterlocking blocks. A modified chord circle block 12 is shown in FIG. 5having a planar and parallel front face 13 and back face 14 and a planarand parallel top wall 15 and bottom wall 16 which latter walls define atrapezoidal configuration in plan. Again, as in all blocks according thepresent concept, the configuration of a transverse cross section of theblock is that of a parallelogram with the front and back faces inclinedwith respect to the horizontal, an amount approximately that of theladle shell inclination.

A tongue and groove, or interlocking block 17, is shown in FIG. 3 andincludes planar and parallel top and bottom walls 18 and 19respectively, together with front and back faces 20 and 21, which latterfaces are inclined in a manner similar to the corresponding faces of theother described blocks to provide the cross-sectional configuration of aparallelogram. In this interlocking block 17, it will be understood thatthe tongue and groove arrangement at the ends of the block will bedisposed parallel to front and back faces 20 and 21, respectively.

The manner of installing the lining 4 of the present invention will beapparent in view of the foregoing description. The lowermost course ofrefractory blocks is positioned upon the top of the horizontallydisposed working floor lining 3 with the back face of each refractoryblock being abutted against the adjacent safety lining or ladle shelland each subsequent course of block is positioned upon the next lowestcourse with the edges of each top and bottom wall contacting one anothersuch that a smooth continuous lining face 5 is produced resulting in alining face or surface parallel to the inclined surface of the ladleshell and yielding a working side lining 4 of the most stable naturewithout any corbelling effect.

I claim:

1. A ladle comprising a conically curved side shell inclined upwardlyand outwardly from a horizontal base lining, said side shellsubstantially circular in plan and inclined from the vertical at asubstantially fixed angle between approximately 440, said shell having adiameter of less than approximately inches, a working side liningdisposed adjacent substantially the entirety of the interior surface ofsaid shell, said side lining including a plurality of vertically stackedcourses of refractory blocks, each said course in turn including aplurality of laterally adjacent refractory blocks, said blocks ofvertically adjacent courses of congruent configuration, each said blockhaving a planar and congruent top and bottom walls parallel to oneanother, parallel front and back faces on each said block both angularlydisposed with respect to said block top and bottom walls, each saidblock having a pair of end walls disposed in vertical planes, and saidblock top and bottom walls are parallel to the horizontal plane of saidbase lining while said angularly disposed front and back faces arevertically inclined an amount substantially corresponding to saidinclination of said shell side from the horizontal, whereby the lateraledges of said front faces of adjacent blocks are contiguous throughoutsaid side lining.

2. A ladle according to claim 1, wherein said blocks are arcuate inplan.

3. A ladle according to claim 1, wherein said blocks are trapezoidal inplan.

4. A ladle according to claim 1, wherein said blocks are provided withan interlocking tongue and groove structure on the juxtaposed endsthereof.

5. A ladle according to claim 1, wherein a refractory safety lining isdisposed between the back face of said lining and said shell.

1. A ladle comprising a conically curved side shell inclined upwardlyand outwardly from a horizontal base lining, said side shellsubstantially circular in plan and inclined from the vertical at asubstantially fixed angle between approximately 4*10* , said shellhaving a diameter of less than approximately 90 inches, a working sidelining disposed adjacent substantially the entirety of the interiorsurface of said shell, said side lining including a plurality ofvertically stacked courses of refractory blocks, each said course inturn including a plurality of laterally adjacent refractory blocks, saidblocks of vertically adjacent courses of congruent configuration, eachsaid block having a planar and congruent top and bottom walls parallelto one another, parallel front and back faces on each said block bothangularly disposed with respect to said block top and bottom walls, eachsaid block having a pair of end walls disposed in vertical planes, andsaid block top and bottom walls are parallel to the horizontal plane ofsaid base lining while said angularly disposed front and back faces arevertically inclined an amount substantially corresponding to saidinclination of said shell side from the horizontal, whereby the lateraledges of said front faces of adjacent blocks are contiguous throughoutsaid side lining.
 2. A ladle according to claim 1, wherein said blocksare arcuate in plan.
 3. A ladle according to claim 1, wherein saidblocks are trapezoidal in plan.
 4. A ladle according to claim 1, whereinsaid blocks are provided with an interlocking tongue and groovestructure on the juxtaposed ends thereof.
 5. A ladle according to claim1, wherein a refractory safety lining is disposed between the back faceof said lining and said shell.